1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor structure, and more particularly to a method of manufacturing an L-shaped spacer.
2. Description of Related Art
With the enhancement of the functions of computers and electronic products, the application circuits have become complicated than ever. In consideration of costs and stability, the required density of transistors within the integrated circuit is significantly increased. However, establishment of high-density integrated circuit cannot be achieved by merely reducing the size of components of the integrated circuit, for any alteration in layout of the integrated circuit is restricted by the design rule and the manufacturing standard. Moreover, the physical characteristics of the components should also be taken into account.
Referring to FIG. 1, a metal-semiconductor-transistor (MOS) is taken for an example. The distance between two MOSs 110 and 120 on a substrate 100 is rather close. Spacers 117 and 127 are disposed at respective sidewalls of a gate 115 of the MOS 110 and a gate 125 of the MOS 120. Since the spacers 117 and 127 present an arc shape, the distance between the two MOSs is even closer. Thereby, during a subsequent process of fabricating a contact window 140, it is very likely to cause an undesired filling, bringing about formation of voids 130. Furthermore, since the sidewalls of gates 115 and 125 may have uneven profiles, current leakage is expectable under a high voltage operation, which affects the electrical performance of devices.